Add support for coinbase inputs on block reward transactions

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 - fixed: Improper handling of WebSocket message processing errors, causing sync-halting.
+- fixed: Add support for processing coinbase inputs on block reward transactions.
 
 ## 3.4.3 (2024-10-15)
 

src/common/utxobased/engine/UtxoEngineProcessor.ts

@@ -1257,43 +1257,60 @@ const processTransactionResponse = (
   args: { txResponse: TransactionResponse }
 ): TransactionData => {
   const { txResponse } = args
-  const inputs = txResponse.vin.map(vin => {
+
+  let outputTotalValue = '0'
+  const outputs: TransactionData['outputs'] = txResponse.vout.map(vout => {
     const scriptPubkey =
-      // Note: Blockbook has empirically not sent a hex value as the
-      // scriptPubkey for vins. If we discover this to be changed for some
-      // cases, we may want to use the `hex` field as an optimization.
+      vout.hex ??
       asMaybe(
         raw => validScriptPubkeyFromAddress(raw),
         'unknown'
       )({
-        address: vin.addresses[0],
+        address: vout.addresses[0],
         coin: common.pluginInfo.coinInfo.name
       })
+    outputTotalValue = add(outputTotalValue, vout.value)
     return {
-      txId: vin.txid,
-      outputIndex: vin.vout,
-      n: vin.n,
+      n: vout.n,
       scriptPubkey,
-      sequence: vin.sequence,
-      amount: vin.value
+      amount: vout.value
     }
   })
-  const outputs = txResponse.vout.map(vout => {
+
+  const inputs: TransactionData['inputs'] = txResponse.vin.map(vin => {
+    // Handle coinbase input
+    if (!vin.isAddress) {
+      return {
+        amount: outputTotalValue,
+        n: 0,
+        outputIndex: 4294967295,
+        scriptPubkey: '', // Maybe there's a bogus scriptPubkey we can use here?
+        sequence: vin.sequence,
+        txId: '0000000000000000000000000000000000000000000000000000000000000000'
+      }
+    }
+
     const scriptPubkey =
-      vout.hex ??
+      // Note: Blockbook has empirically not sent a hex value as the
+      // scriptPubkey for vins. If we discover this to be changed for some
+      // cases, we may want to use the `hex` field as an optimization.
       asMaybe(
         raw => validScriptPubkeyFromAddress(raw),
         'unknown'
       )({
-        address: vout.addresses[0],
+        address: vin.addresses[0],
         coin: common.pluginInfo.coinInfo.name
       })
     return {
-      n: vout.n,
+      txId: vin.txid,
+      outputIndex: vin.vout,
+      n: vin.n,
       scriptPubkey,
-      amount: vout.value
+      sequence: vin.sequence,
+      amount: vin.value
     }
   })
+
   return {
     txid: txResponse.txid,
     hex: txResponse.hex,

src/common/utxobased/network/blockbookApi.ts

@@ -1,12 +1,14 @@
 import {
   asArray,
   asBoolean,
+  asEither,
   asMaybe,
   asNumber,
   asObject,
   asOptional,
   asString,
   asUnknown,
+  asValue,
   Cleaner,
   uncleaner
 } from 'cleaners'
@@ -57,16 +59,24 @@ export interface BlockbookTransaction {
   confirmations: number
   blockTime: number
   fees: string
-  vin: Array<{
-    txid: string
-    sequence: number
-    n: number
-    vout: number
-    addresses: string[]
-    isAddress: boolean
-    value: string
-    hex?: string
-  }>
+  vin: Array<
+    | {
+        addresses: string[]
+        hex?: string
+        isAddress: true
+        n: number
+        sequence: number
+        txid: string
+        value: string
+        vout: number
+      }
+    | {
+        coinbase: string
+        isAddress: false
+        n: number
+        sequence: number
+      }
+  >
   vout: Array<{
     n: number
     value: string
@@ -85,22 +95,36 @@ export const asBlockbookTransaction = (
     blockTime: asNumber,
     fees: asString,
     vin: asArray(
-      asObject({
-        txid: asString,
-        // Empirically observed omitted sequence is possible for when sequence is zero.
-        // Is the case for tx `19ecc679cfc7e71ad616a22bbee96fd5abe8616e4f408f1f5daaf137400ae091`.
-        sequence: asOptional(asNumber, 0),
-        n: asNumber,
-        // If Blockbook doesn't provide vout, assume 0. Empirically observed
-        // case for tx `fefac8c22ba1178df5d7c90b78cc1c203d1a9f5f5506f7b8f6f469fa821c2674`
-        // which has no `vout` for input in WebSocket response payload but block
-        // will show the input's vout value to be `0`.
-        vout: asOptional(asNumber, 0),
-        addresses: asArray(asAddress),
-        isAddress: asBoolean,
-        value: asString,
-        hex: asOptional(asString)
-      })
+      asEither(
+        // Address input:
+        asObject({
+          addresses: asArray(asAddress),
+          // `isAddress` is a boolean flag that indicates whether the input is an address.
+          // And therefore has `addresses` field. If `isAddress` is false, then the input is likely a coinbase input.
+          isAddress: asValue(true),
+          // This is the index of the input. Not to be confused with the index of the previous output (vout).
+          n: asNumber,
+          // Empirically observed omitted sequence is possible for when sequence is zero.
+          // Is the case for tx `19ecc679cfc7e71ad616a22bbee96fd5abe8616e4f408f1f5daaf137400ae091`.
+          sequence: asOptional(asNumber, 0),
+          txid: asString,
+          value: asString,
+          // If Blockbook doesn't provide vout, assume 0. Empirically observed
+          // case for tx `fefac8c22ba1178df5d7c90b78cc1c203d1a9f5f5506f7b8f6f469fa821c2674`
+          // which has no `vout` for input in WebSocket response payload but block
+          // will show the input's vout value to be `0`.
+          vout: asOptional(asNumber, 0),
+          hex: asOptional(asString)
+        }),
+        // Coinbase input:
+        asObject({
+          // Coinbase input is a string of hex data (see example c6e617656b7b6d9fdcf8800fb5370479e5aceea4b6fe2fd74bd7bb0f3f2c64db)
+          coinbase: asString,
+          isAddress: asValue(false),
+          n: asNumber,
+          sequence: asNumber
+        })
+      )
     ),
     vout: asArray(
       asObject({

test/common/utxobased/network/Blockbook.spec.ts

@@ -272,14 +272,16 @@ describe('Blockbook', function () {
   })
 
   describe('fetchTransaction', function () {
-    const satoshiHash =
-      '3ed86f1b0a0a6fe180195bc1f93fd9d0801aea8c8ad5018de82c026dc21e2b15'
     it('should fetch details from a transaction hash', async function () {
+      const satoshiHash =
+        '3ed86f1b0a0a6fe180195bc1f93fd9d0801aea8c8ad5018de82c026dc21e2b15'
       const tx = await blockbook.fetchTransaction(satoshiHash)
 
       tx.txid.should.equal(satoshiHash)
       tx.fees.should.equal('226')
       tx.blockHeight.should.equal(651329)
+      tx.vin[0].isAddress.should.equal(true)
+      if (!tx.vin[0].isAddress) throw new Error('Type assertion failed')
       tx.vin[0].value.should.equal('97373')
       tx.vin[0].txid.should.equal(
         'fac5994d454817db2daec796cfa79cce670a372e7505fdef2a259289d5df0814'
@@ -289,12 +291,32 @@ describe('Blockbook', function () {
       tx.vin[0].addresses.should.eqls([
         'bc1qg6lwu6c8yqhhw7rrq69akknepxcft09agkkuqv'
       ])
-      tx.vin[0].isAddress.should.equal(true)
       tx.vin[0].value.should.equal('97373')
 
       tx.vout[1].value.should.equal('95000')
       tx.should.have.property('confirmations')
       tx.should.have.property('blockTime')
     })
+
+    it('should fetch details from a coinbase transaction hash', async function () {
+      const blockRewardTxid =
+        'c6e617656b7b6d9fdcf8800fb5370479e5aceea4b6fe2fd74bd7bb0f3f2c64db'
+      const tx = await blockbook.fetchTransaction(blockRewardTxid)
+
+      tx.txid.should.equal(blockRewardTxid)
+      tx.fees.should.equal('0')
+      tx.blockHeight.should.equal(868078)
+      tx.vin[0].isAddress.should.equal(false)
+      if (tx.vin[0].isAddress) throw new Error('Type assertion failed')
+      tx.vin[0].coinbase.should.equal(
+        '03ee3e0d1e3c204f4345414e2e58595a203e0f456c656b74726f6e20456e657267790007155cb4e4ff33420eb387b0ccf1ee1567020000000000'
+      )
+      expect(tx.vin[0].sequence).to.equal(4294967295)
+      tx.vin[0].n.should.equal(0)
+
+      tx.vout[1].value.should.equal('135549329')
+      tx.should.have.property('confirmations')
+      tx.should.have.property('blockTime')
+    })
   })
 })